:root{color-scheme:light;--bg: #f4f6fb;--surface: #ffffff;--surface-strong: #f9fbff;--surface-muted: #edf2f8;--border: #d9e1ed;--border-strong: #c8d3e3;--text: #18212f;--text-muted: #647184;--accent: #1f6feb;--accent-strong: #1658c8;--accent-soft: #e8f1ff;--success-bg: #f0fbf4;--success-border: #8ac9a7;--success-text: #17623a;--warning-bg: #fff7d6;--warning-border: #e6bc35;--warning-text: #765600;--danger: #b42318;--danger-bg: #fff3f3;--danger-border: #efb1b1;--danger-text: #9f1f18;--shadow: 0 18px 40px rgba(35, 52, 75, .12);color:var(--text);background:var(--bg);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-synthesis:none;text-rendering:optimizeLegibility}:root[data-theme=dark]{color-scheme:dark;--bg: #10151f;--surface: #171d29;--surface-strong: #1e2635;--surface-muted: #252f40;--border: #2f3a4d;--border-strong: #43516a;--text: #edf3fb;--text-muted: #a5b1c4;--accent: #68a4ff;--accent-strong: #8bbaff;--accent-soft: #1d3152;--success-bg: #14291d;--success-border: #3f8f63;--success-text: #8be3a8;--warning-bg: #352b13;--warning-border: #a57b15;--warning-text: #ffd66e;--danger: #ff9189;--danger-bg: #361b1d;--danger-border: #8a3a3d;--danger-text: #ffaaa4;--shadow: 0 18px 44px rgba(0, 0, 0, .3)}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh;background:var(--bg)}a{color:inherit;text-decoration:none}button,.button{display:inline-flex;align-items:center;justify-content:center;min-height:44px;border:0;border-radius:8px;padding:0 18px;background:var(--accent);color:#fff;font:inherit;font-weight:700;cursor:pointer;transition:background .16s ease,border-color .16s ease,color .16s ease,transform .16s ease}button:hover,.button:hover{background:var(--accent-strong)}button:active,.button:active{transform:translateY(1px)}button:disabled{cursor:not-allowed;opacity:.55}button.secondary{border:1px solid var(--border);background:var(--surface-muted);color:var(--text)}button.secondary:hover{background:var(--surface-strong)}button.small{min-height:36px;padding:0 12px}button:focus-visible,a:focus-visible,input:focus-visible{outline:3px solid color-mix(in srgb,var(--accent) 35%,transparent);outline-offset:2px}input{width:100%;min-height:44px;border:1px solid var(--border);border-radius:8px;padding:0 12px;background:var(--surface);color:var(--text);font:inherit}h1,h2,h3,p{margin-top:0}.login-screen{min-height:100vh;display:grid;place-items:center;padding:24px;background:var(--bg)}.login-card{width:min(100%,420px);display:grid;gap:18px;border:1px solid var(--border);border-radius:8px;padding:28px;background:var(--surface);box-shadow:var(--shadow)}.login-card h1{margin-bottom:0;font-size:2rem}.login-card label{display:grid;gap:8px;font-weight:700}.app-shell{min-height:100vh;background:var(--bg)}.sidebar{display:none}.content-shell{min-width:0}.topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:64px;padding:12px 16px;background:color-mix(in srgb,var(--surface) 94%,transparent);border-bottom:1px solid var(--border);-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.topbar div:first-child{min-width:0;display:grid;gap:2px}.topbar strong{line-height:1.1}.topbar span{color:var(--text-muted);font-size:.9rem}.topbar-actions{display:flex;align-items:center;gap:8px;flex-shrink:0}.icon-button,.logout-button,.dialog-close{min-width:40px;min-height:40px;border:1px solid var(--border);padding:0;background:var(--surface-strong);color:var(--text)}.icon-button:hover,.logout-button:hover,.dialog-close:hover{border-color:var(--border-strong);background:var(--surface-muted)}.logout-button{gap:8px;width:40px;overflow:hidden}.logout-button span{display:none}.container{width:min(1120px,100%);margin:0 auto;padding:24px 16px 104px}.mobile-tabbar{position:fixed;right:10px;bottom:10px;left:10px;z-index:30;display:grid;grid-template-columns:repeat(5,1fr);gap:4px;min-height:66px;border:1px solid var(--border);border-radius:8px;padding:6px;background:color-mix(in srgb,var(--surface) 96%,transparent);box-shadow:var(--shadow);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px)}.mobile-tabbar a{display:grid;place-items:center;gap:3px;border-radius:8px;padding:6px 2px;color:var(--text-muted);font-size:.72rem;font-weight:800}.mobile-tabbar a.active{background:var(--accent-soft);color:var(--accent-strong)}.page-stack{display:grid;gap:22px}.eyebrow{margin-bottom:6px;color:var(--text-muted);font-size:.82rem;font-weight:800;text-transform:uppercase}.stats-grid,.action-grid,.theme-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:14px}.stat-card,.question-card,.error-card,.theme-card,.empty-state,.feedback{border:1px solid var(--border);border-radius:8px;background:var(--surface)}.stat-card{display:grid;gap:8px;padding:18px}.stat-card span,.muted{color:var(--text-muted)}.stat-card strong{font-size:1.8rem}.theme-card{min-height:92px;display:flex;align-items:center;justify-content:center;padding:18px;background:var(--surface);font-size:1.2rem;font-weight:800}.theme-card:hover{border-color:var(--accent);background:var(--accent-soft)}.session-header{display:flex;align-items:stretch;flex-direction:column;gap:14px}.timers{display:grid;gap:6px;color:var(--text-muted)}.question-card{display:grid;gap:20px;padding:clamp(18px,4vw,28px)}.question-card h2{font-size:clamp(1.25rem,2vw,1.65rem);line-height:1.35}.question-meta{display:flex;gap:8px;flex-wrap:wrap}.question-meta span,.error-card span{border-radius:999px;padding:5px 9px;background:var(--accent-soft);color:var(--accent-strong);font-size:.8rem;font-weight:800}.alternatives{display:grid;gap:10px}.alternative{position:relative;min-height:56px;justify-content:flex-start;border:1px solid var(--border);background:var(--surface-strong);color:var(--text);text-align:left;padding-left:16px}.alternative:hover:not(.locked){border-color:var(--border-strong);background:var(--surface-muted)}.alternative.selected{border-color:var(--accent-strong);background:color-mix(in srgb,var(--accent-soft) 82%,var(--surface) 18%);color:var(--text);box-shadow:inset 0 0 0 2px color-mix(in srgb,var(--accent-strong) 58%,transparent);transform:translateY(-1px)}.alternative.selected:before{content:"";position:absolute;left:10px;top:50%;width:10px;height:10px;border-radius:999px;background:var(--accent-strong);transform:translateY(-50%)}.alternative.locked{cursor:default}.alternative.locked:not(.correct):not(.incorrect){color:var(--text-muted)}.alternative.correct,.alternative.correct:hover{border-color:var(--success-border);background:var(--success-bg);color:var(--success-text)}.alternative.incorrect,.alternative.incorrect:hover{border-color:var(--danger-border);background:var(--danger-bg);color:var(--danger-text)}.difficulty-badge.easy{background:var(--success-bg);color:var(--success-text)}.difficulty-badge.medium{background:var(--warning-bg);color:var(--warning-text)}.difficulty-badge.hard{background:var(--danger-bg);color:var(--danger-text)}.feedback{display:grid;gap:8px;padding:18px}.feedback h2{margin-bottom:0}.feedback.compact{align-items:center;grid-template-columns:1fr}.feedback.ok{border-color:var(--success-border);background:var(--success-bg)}.feedback.wrong{border-color:var(--danger-border);background:var(--danger-bg)}.empty-state{display:grid;justify-items:start;gap:14px;padding:28px}.list-section{display:grid;gap:12px}.error-card{display:grid;gap:8px;padding:16px}.error-card h3{margin-bottom:4px;font-size:1rem}.error-card p{margin-bottom:0}.table-wrap{overflow-x:auto;border:1px solid var(--border);border-radius:8px;background:var(--surface)}table{width:100%;border-collapse:collapse;min-width:620px}th,td{padding:14px;border-bottom:1px solid var(--border);text-align:left}th{color:var(--text-muted);font-size:.85rem;text-transform:uppercase}.error{color:var(--danger);font-weight:700}.modal-backdrop{position:fixed;top:0;right:0;bottom:0;left:0;z-index:60;display:grid;place-items:center;padding:18px;background:#080c148c}.confirm-dialog{position:relative;width:min(100%,380px);display:grid;gap:14px;border:1px solid var(--border);border-radius:8px;padding:24px;background:var(--surface);box-shadow:var(--shadow)}.dialog-close{position:absolute;top:12px;right:12px;min-width:34px;min-height:34px}.dialog-icon{width:44px;height:44px;display:grid;place-items:center;border-radius:8px;background:var(--accent-soft);color:var(--accent-strong)}.confirm-dialog h2{margin-bottom:0;padding-right:36px}.confirm-dialog p{margin-bottom:0;color:var(--text-muted)}.dialog-actions{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:4px}@media(min-width:640px){.logout-button{width:auto;padding:0 12px}.logout-button span{display:inline;color:inherit;font-size:.92rem}.session-header{align-items:flex-start;flex-direction:row;justify-content:space-between}.timers{text-align:right}.action-grid{grid-template-columns:repeat(auto-fit,minmax(180px,1fr))}}@media(min-width:900px){.app-shell{display:grid;grid-template-columns:248px minmax(0,1fr)}.sidebar{position:sticky;top:0;height:100vh;display:flex;flex-direction:column;gap:24px;border-right:1px solid var(--border);padding:18px 14px;background:var(--surface)}.sidebar-brand{display:flex;align-items:center;gap:12px;padding:4px 4px 8px}.brand-mark{width:42px;height:42px;display:grid;place-items:center;border-radius:8px;background:var(--accent);color:#fff;font-weight:900}.sidebar-brand div{display:grid;gap:2px}.sidebar-brand span:not(.brand-mark),.sidebar-footer{color:var(--text-muted);font-size:.88rem}.sidebar-nav{display:grid;gap:6px}.sidebar-nav a{display:flex;align-items:center;gap:10px;border-radius:8px;padding:11px 12px;color:var(--text-muted);font-weight:800}.sidebar-nav a:hover{background:var(--surface-strong);color:var(--text)}.sidebar-nav a.active{background:var(--accent-soft);color:var(--accent-strong)}.sidebar-footer{margin-top:auto;border-top:1px solid var(--border);padding:14px 8px 2px}.mobile-tabbar{display:none}.topbar{min-height:70px;padding:14px 32px}.topbar div:first-child strong{display:none}.container{padding:32px clamp(28px,4vw,48px) 56px}}